* Support unicode emojis and remove emojify.js

This PR replaces all use of emojify.js and adds unicode emoji support to various areas of gitea.

This works in a few ways:

First it adds emoji parsing support into gitea itself. This allows us to

 * Render emojis from valid alias (😄)
 * Detect unicode emojis and let us put them in their own class with proper aria-labels and styling
 * Easily allow for custom "emoji"
 * Support all emoji rendering and features without javascript
 * Uses plain unicode and lets the system render in appropriate emoji font
 * Doesn't leave us relying on external sources for updates/fixes/features

That same list of emoji is also used to create a json file which replaces the part of emojify.js that populates the emoji search tribute. This file is about 35KB with GZIP turned on and I've set it to load after the page renders to not hinder page load time (and this removes loading emojify.js also)

For custom "emoji" it uses a pretty simple scheme of just looking for /emojis/img/name.png where name is something a user has put in the "allowed reactions" setting we already have. The gitea reaction that was previously hard coded into a forked copy of emojify.js is included and works as a custom reaction under this method.

The emoji data sourced here is from https://github.com/github/gemoji which is the gem library Github uses for their emoji rendering (and a data source for other sites). So we should be able to easily render any emoji and :alias: that Github can, removing any errors from migrated content. They also update it as well, so we can sync when there are new unicode emoji lists released.

I've included a slimmed down and slightly modified forked copy of https://github.com/knq/emoji to make up our own emoji module. The code is pretty straight forward and again allows us to have a lot of flexibility in what happens.

I had seen a few comments about performance in some of the other threads if we render this ourselves, but there doesn't seem to be any issue here. In a test it can parse, convert, and render 1,000 emojis inside of a large markdown table in about 100ms on my laptop (which is many more emojis than will ever be in any normal issue). This also prevents any flickering and other weirdness from using javascript to render some things while using go for others.

Not included here are image fall back URLS. I don't really think they are necessary for anything new being written in 2020. However, managing the emoji ourselves would allow us to add these as a feature later on if it seems necessary.

Fixes: https://github.com/go-gitea/gitea/issues/9182
Fixes: https://github.com/go-gitea/gitea/issues/8974
Fixes: https://github.com/go-gitea/gitea/issues/8953
Fixes: https://github.com/go-gitea/gitea/issues/6628
Fixes: https://github.com/go-gitea/gitea/issues/5130

* add new shared function emojiHTML

* don't increase emoji size in issue title

* Update templates/repo/issue/view_content/add_reaction.tmpl

Co-Authored-By: 6543 <6543@obermui.de>

* Support for emoji rendering in various templates

* Render code and review comments as they should be

* Better way to handle mail subjects

* insert unicode from tribute selection

* Add template helper for plain text when needed

* Use existing replace function I forgot about

* Don't include emoji greater than Unicode Version 12

Only include emoji and aliases in JSON

* Update build/generate-emoji.go

* Tweak regex slightly to really match everything including random invisible characters. Run tests for every emoji we have

* final updates

* code review

* code review

* hard code gitea custom emoji to match previous behavior

* Update .eslintrc

Co-Authored-By: silverwind <me@silverwind.io>

* disable preempt

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Show Signer in commit lists and add basic trust

Show the avatar of the signer in the commit list pages as we do not
enforce that the signer is an author or committer. This makes it
clearer who has signed the commit.

Also display commits signed by non-members differently from
members and in particular make it clear when a non-member signer
is different from the committer to help reduce the risk of
spoofing.

Signed-off-by: Andrew Thornton <art27@cantab.net>

* ensure orange text and background is available

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Update gpg_key.go

* Update models/gpg_key.go

* Apply suggestions from code review

* Require team collaborators to have access to UnitTypeCode

* as per @6543

* fix position of sha as per @silverwind

* as per @guillep2k

* Truncate long commit message header

* Fix overflow in view commit table

* Use @media less

* Further improvements

* Fix the commit message on small screens

* adjust width of minimal table

* Add octicon SVG sprite

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Static prefix

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* SVG for all repo icons

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* make vendor

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Swap out octicons

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Move octicons to top of less imports

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Fix JS

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Definitely not a search/replace

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Missed regex

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Move to more generic calls and webpack

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* make svg -> make webpack

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Remove svg-sprite

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Update tests

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Missed a test

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Remove svg from makefile

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Suggestions

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Attempt to fix test

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Update tests

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Revert timetracking test

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Swap .octicon for .svg in less

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Add aria-hidden

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Replace mega-octicon

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Fix webpack globbing on Windows

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Revert

Co-Authored-By: silverwind <me@silverwind.io>

* Fix octions from upstream

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Fix Vue and missed JS function

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Add JS helper and PWA

Signed-off-by: jolheiser <john.olheiser@gmail.com>

* Preload SVG

Signed-off-by: jolheiser <john.olheiser@gmail.com>

Co-authored-by: silverwind <me@silverwind.io>
Co-authored-by: techknowlogick <matti@mdranta.net>

This PR fixes #7598 by providing a configurable way of signing commits across the Gitea instance. Per repository configurability and import/generation of trusted secure keys is not provided by this PR - from a security PoV that's probably impossible to do properly. Similarly web-signing, that is asking the user to sign something, is not implemented - this could be done at a later stage however.

## Features
- [x] If commit.gpgsign is set in .gitconfig sign commits and files created through repofiles. (merges should already have been signed.)
- [x] Verify commits signed with the default gpg as valid
- [x] Signer, Committer and Author can all be different
    - [x] Allow signer to be arbitrarily different - We still require the key to have an activated email on Gitea. A more complete implementation would be to use a keyserver and mark external-or-unactivated with an "unknown" trust level icon.
- [x] Add a signing-key.gpg endpoint to get the default gpg pub key if available
    - Rather than add a fake web-flow user I've added this as an endpoint on /api/v1/signing-key.gpg
    - [x] Try to match the default key with a user on gitea - this is done at verification time
- [x] Make things configurable?
    - app.ini configuration done
    - [x] when checking commits are signed need to check if they're actually verifiable too
- [x] Add documentation

I have decided that adjusting the docker to create a default gpg key is not the correct thing to do and therefore have not implemented this.

* Supports tags when comparing commits or branches

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Hide headline when only comparing and don't load unused data

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Merges compare logics to allow comparing branches, commits and tags with eachother

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Display branch or tag instead of commit when used for comparing

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Show pull request form after click on button

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Transfers relevant pull.go changes from master to compare.go

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Fixes error when comparing forks against a commit or tag

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Removes console.log from JavaScript file

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Show icon next to commit reference when comparing branch or tag

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Updates css file

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Fixes import order

* Renames template variable

* Update routers/repo/compare.go

Co-Authored-By: zeripath <art27@cantab.net>

* Update from master

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Allow short-shas in compare

* Renames prInfo to compareInfo

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Check PR permissions only if compare is pull request

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Adjusts comment

Signed-off-by: Mario Lubenka <mario.lubenka@googlemail.com>

* Use compareInfo instead of prInfo